Re: [chrony-users] Debian stretch read only rootfs?

[Matthew Eshleman <matthew@xxxxxxxxxxxxxxxxxxxxxxxx>]

Hi all,

Resolved, thank you for the helpful responses.

Ultimately needed tmpfs for:

# df
Filesystem     1K-blocks   Used Available Use% Mounted on
/dev/root         226688 226688         0 100% /
devtmpfs          167400      0    167400   0% /dev
tmpfs             167912      0    167912   0% /dev/shm
tmpfs             167912   2244    165668   2% /run
tmpfs               5120      8      5112   1% /run/lock
tmpfs             167912      0    167912   0% /sys/fs/cgroup
tmpfs               1024      4      1020   1% /var/lib/dhcp
tmpfs               1024     12      1012   2% /var/log
tmpfs               2048     16      2032   1% /run_etc_tmpfs
tmpfs             167912      0    167912   0% /tmp
overlay             2048     16      2032   1% /etc

Then, the following fix/repair:

https://github.com/kata-containers/osbuilder/pull/295/commits/456be6709443221088ce7ad5f7c91cffe4d4774e

i.e creating a link from /var/tmp to /tmp.

That appeared to be the final step/need in this. I'm now acquiring and syncing to NTP in this production read only rootfs configuration.

Again, thank you very much!

Matthew

On Fri, Feb 4, 2022 at 1:57 PM Anders Mikkelsen <anders@xxxxxxxxxxx> wrote:

Hello,

I have no solid advice for you, but I have experienced something along the same lines... on another platform, but with systemd. It may be worthwhile to check the systemd tmpfiles settings.

The chrony package we used installs a tmpfile directive for systemd (e.g. /usr/lib/tmpfiles.d/chrony.d)

Do you find a similar file in your chrony package, and if so, what is the path specified in it?

If so, what does
"systemd-tmpfiles --create chrony.conf"
give you?

Regards,
Anders Mikkelsen


----- Original Message -----
From: "Matthew Eshleman" <matthew@xxxxxxxxxxxxxxxxxxxxxxxx>
To: chrony-users@xxxxxxxxxxxxxxxxxxxx
Sent: Friday, 4 February, 2022 17:06:33
Subject: [chrony-users] Debian stretch read only rootfs?

Hello all,

I've been experimenting with chrony for an embedded linux system and we
have decided to move forward, adding NTP as a feature to this device, using
chrony. Previously this device only supported human manual time entry. All
experiments to-date have been on a development unit with a fairly normal
read/write debian rootfs.

This device is currently using debian stretch, and we use a multistrap
approach to generate our rootfs, which is then packaged into a read only
rootfs using squashfs for our production configuration.

In my attempts so far, chrony fails to start. We have a ramfs overlay for
/etc/ and I added one for /var/lib/chrony as well. The logs/journal did not
point me to the exact folder/file that is blocking chrony from starting
with a read only root filesystem, and I didn't find specific hints via
google (except for some redhat patch, that I do not believe applies here...)

Additionally, I configured chrony to use a drift file that is on a separate
read/write partition.

What additional files/folders does chrony need to be read/write?

Logs and such are below:

Feb 04 15:19:34 M systemd[1]: Started Raise network interfaces.
Feb 04 15:19:34 M systemd[1]: Reached target Network.
Feb 04 15:19:34 M systemd[1]: chrony.service: Failed to run 'start' task:
Read-only file system
Feb 04 15:19:34 M systemd[1]: Failed to start chrony, an NTP client/server.
Feb 04 15:19:35 M systemd[1]: chrony.service: Unit entered failed state.
Feb 04 15:19:35 M systemd[1]: chrony.service: Failed with result
'resources'.

systemctl status chrony
● chrony.service - chrony, an NTP client/server
   Loaded: loaded (/lib/systemd/system/chrony.service; enabled; vendor
preset: e
   Active: failed (Result: resources)
     Docs: man:chronyd(8)
           man:chronyc(1)
           man:chrony.conf(5)

~# df
Filesystem     1K-blocks   Used Available Use% Mounted on
/dev/root         257664 257664         0 100% /
devtmpfs          167400      0    167400   0% /dev
tmpfs             167912      0    167912   0% /dev/shm
tmpfs             167912    960    166952   1% /run
tmpfs               5120      8      5112   1% /run/lock
tmpfs             167912      0    167912   0% /sys/fs/cgroup
tmpfs               1024      0      1024   0% /var/lib/chrony
tmpfs               2048     16      2032   1% /run_etc_tmpfs
tmpfs             167912      0    167912   0% /tmp
tmpfs               1024      4      1020   1% /var/lib/dhcp
overlay             2048     16      2032   1% /etc
/dev/mmcblk0p5    122835   2612    113670   3% /media/settings

chronyd version 3.0 (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER
+SECHASH +SIGND +ASYNCDNS +IPV6 -DEBUG)

Thank you very much for any pointers, tips, etc.

Best regards,

Matthew

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